Its steep pitches are known to let loose slides capable of crossing the Big Cottonwood Canyon road. And this time of year, afternoon heating can cause the sunbaked slopes of God's Lawnmower and Kessler Slabs to move.

"A big part of what we do on a regular basis is travel to or near [avalanche] starting zones to assess conditions that affect the decisions we'll be making this coming week when it snows again," Patterson's boss, Liam Fitzgerald, said Friday afternoon.

Fitzgerald, supervisor of the Utah Department of Transportation's highway avalanche safety program, spoke while awaiting more detailed information from a team of avalanche experts inspecting the slide zone for clues about what befell the 34-year-old Summit Park resident, a husband and father of a young girl.

Patterson was traveling alone Thursday, a day when the high hit 41 degrees at Alta. Solo surveys of the backcountry are not uncommon for the seven avalanche forecasters UDOT relies on to assess conditions in Little Cottonwood and Big Cottonwood canyons, renowned worldwide for their proclivity to slide (UDOT has two more avalanche forecasters in Provo Canyon).

"Sometimes they go out in pairs," said UDOT spokesman Adan Carrillo. "But they have a lot of terrain to cover so sometimes they go alone. When they do, there are protocols they have to follow so they don't do certain things by themselves. â¦ They communicate where they are going to be, for how long and so forth."

So when Patterson's family informed his co-workers that he had not returned home from work Thursday, "they knew exactly where to look for him," Carrillo said. "And that was exactly where he was."

Searchers in a helicopter spotted his body in an avalanche run-out  with a deployed air bag, the Utah Avalanche Center reported  just before sunset. By 1 a.m. Friday, a search and rescue team had removed Patterson's body.

Fitzgerald said Patterson had not been within Kessler Peak's biggest avalanche path but was "traveling on the ridgeline adjacent to it." Warm weather likely played a role  "heating was affecting the snow everywhere yesterday," he added  but a more complete picture depends on what was found by the experts from the Avalanche Center and UDOT in their analysis of the accident site.

Gov. Gary Herbert called him "a dedicated state employee who was admired and respected for his professionalism and expertise in making our canyons safer." Herbert said he spoke for all Utahns in offering condolences to Patterson's wife, Renea, and their daughter.

Becca Babicz never met Patterson but appreciates the work forecasters do all winter. "Really sad day for the Utah backcountry community," she tweeted. "Thoughts and prayers go out to Craig Patterson's friends and family."

A visiting professor in the University of Utah's business school, Jennifer Overbeck rented a home in Millcreek from Patterson last fall. "He was great  fascinating, down-to-earth, straightforward, the kind of guy who does business with a handshake," she said. "He's not the kind of guy you'd expect to die young. Mortality becomes very salient at a time like this."

Patterson grew up in Switzerland, learned to ski in France, then immersed himself in rock and ice climbing while earning a degree in geology from the University of Miami (Ohio) and exploring the White Mountains of New Hampshire.

After a stint as an avalanche safety instructor and guide in Alaska's Western Chugach Mountains, he came to Utah in 2004 as a rock, ice, mountaineering and ski guide for Utah Mountain Adventure (once called Exum). Two years later, Patterson joined UDOT's avalanche team but remained Utah Mountain Adventure's lead Level 1 avalanche instructor, teaching classes on weekends.

"He was pretty incredible, a well-rounded individual," said his colleague, Claire Gorton. "We have students writing in now who are saying how happy they are that they could have taken classes with him."

That comes as no surprise to Fitzgerald. "Craig was a really positive person, very considerate of his fellow employees, smart and extremely self-motivated, a hard worker and he had a good sense of humor  all the things you'd want in a co-worker."

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